Summary of Results of Development and Validation of Hot Honing System to Provide Improved Engine Performance 2002-01-3299

Operating cylinder bore geometry and finish have been identified by numerous investigators over the years as having the capability to modify oil consumption, blowby, wear, and engine friction. It has also been recognized that cylinder bores, even though machined and honed to a round state at the time the block is produced, change shape when cylinder heads are installed and when the engine reaches normal operating temperatures. The concept of heating the block with a simulated head plate and then honing the cylinder bore to achieve a round bore has been evaluated by race engine builders over the years. A number of Formula One engine builders have utilized cylinder bore geometries which were developed while the bores were honed with the cylinder liner installed in a heated block with a heated hone plate. Review of the published literature and discussions with major race engine builders have indicated that minimal organized information on hot honing techniques, procedures, and associated equipment is available. This paper outlines and summarizes procedures followed, data accumulated, and conclusions developed in this study. Utilizing the procedures outlined, it appears that 1-2% improvement in horsepower can be achieved with a corresponding reduction in power loss in the cylinder kit system in an otherwise well-developed high-performance engine.